99% of technical problems are due to incorrect browser "cache" settings.
The browser cache stores pages downloaded to your computer from the Internet. As you work, Etudes-NG is continually updating and storing pages in a database that is on a remote server, not locally on your computer. The browser must be set to always go out to the server and get new pages from the server and to not use old pages stored on your computer or errors will occur.
Click on the Tools Menu > Select Internet Options
Click on the General tab > Under Browsing History, click on the Delete ... button.
In the Temporary Internet Files area, click the Delete Files ... button to clear the cache. Close that window.
Next, click on the Settings button (still in General > Browsing History area) and check, Every time I visit the webpage.
Change Days to keep pages in history to 0.
Click the OK button at the bottom of the Settings window.
Click the OK button at the bottom of the Internet Options window.
Click on the Tools Menu and select Options
Click on the Advanced icon > Network tab to view the settings.
Enter 1 MB of disc space for the cache and click on the Clear Now button.
Click on the OK Button
Open a browser window, delete the address in the URL bar and type about:config. Press the Return key to see Firefox settings. NOTICE: do not include the http prefix here
Scroll down to browser.cache.check_doc_frequency. It should be set to 1.
If it's not, double click on the text and in the resulting dialogue box, enter 1 and click OK.Close window, exit and restart Firefox to enact the change.